Merge pull request #647 from mcastelino/db_cleanup

Networking: Cleanup the docker plugin database implementation

networking/libsnnet/docker_database.go

@@ -76,47 +76,27 @@ func (db *dbProvider) DbClose() error {
 	return db.DB.Close()
 }
 
-//TODO: There must be a better way to do this (besides reflection)
-func (db *dbProvider) DbMapRebuild(table string, dockerMap interface{}) error {
-	tables := []string{table}
+func (db *dbProvider) DbTableRebuild(table DbTable) error {
+	tables := []string{table.Name()}
 	if err := db.DbTableInit(tables); err != nil {
 		return fmt.Errorf("dbInit failed %v", err)
 	}
 
-	switch dmap := dockerMap.(type) {
-	case *DockerNwMap:
-		dmap.m = make(map[string]*DockerNwVal)
-	case *DockerEpMap:
-		dmap.m = make(map[string]*DockerEpVal)
-	default:
-		return fmt.Errorf("error: invalid map type %T", dmap)
-	}
+	table.NewTable()
 
 	err := db.DB.View(func(tx *bolt.Tx) error {
-		b := tx.Bucket([]byte(table))
+		b := tx.Bucket([]byte(table.Name()))
 
 		err := b.ForEach(func(k, v []byte) error {
 			vr := bytes.NewReader(v)
 
-			switch dmap := dockerMap.(type) {
-			case *DockerNwMap:
-				val := &DockerNwVal{}
-				if err := gob.NewDecoder(vr).Decode(val); err != nil {
-					return fmt.Errorf("Decode Error: %v %v %v", string(k), string(v), err)
-				}
-				glog.Infof("%v key=%v, value=%v\n", table, string(k), val)
-
-				dmap.m[string(k)] = val
-			case *DockerEpMap:
-				val := &DockerEpVal{}
-				if err := gob.NewDecoder(vr).Decode(val); err != nil {
-					return fmt.Errorf("Decode Error: %v %v %v", string(k), string(v), err)
-				}
-				glog.Infof("%v key=%v, value=%v\n", table, string(k), val)
-				dmap.m[string(k)] = val
+			val := table.NewElement()
+			if err := gob.NewDecoder(vr).Decode(val); err != nil {
+				return fmt.Errorf("Decode Error: %v %v %v", string(k), string(v), err)
 			}
+			glog.Infof("%v key=%v, value=%v\n", table, string(k), val)
 
-			return nil
+			return table.Add(string(k), val)
 		})
 		return err
 	})

networking/libsnnet/docker_plugin.go

@@ -137,13 +137,29 @@ var DockerPluginCfg = struct {
 	Timeout: 1 * time.Second,
 }
 
+//DbTable interface that needs to be supported
+//for the table to be handled by the database
+type DbTable interface {
+	// Creates the backing map
+	NewTable()
+
+	// Name of the table as stored in the database
+	Name() string
+
+	// Allocates and returns a single value in the table
+	NewElement() interface{}
+
+	// Add an value to the in memory table
+	Add(k string, v interface{}) error
+}
+
 // A DockerDBProvider represents a persistent data base provider
 // that can be used by the DockerPlugin to store its internal state
 type DockerDBProvider interface {
 	//Initializes the Database
 	DbInit(dir string) error
 	//Populates the DockerPlugin cache from the database
-	DbMapRebuild(table string, dockerMap interface{}) error
+	DbTableRebuild(table DbTable) error
 	//Closes the database
 	DbClose() error
 	//Creates the tables if the tables do not already exist in the database
@@ -181,12 +197,62 @@ type DockerEpMap struct {
 	m map[string]*DockerEpVal //index: Docker End Point UUID
 }
 
+//NewTable creates a new map
+func (d *DockerEpMap) NewTable() {
+	d.m = make(map[string]*DockerEpVal)
+}
+
+//Name provides the name of the map
+func (d *DockerEpMap) Name() string {
+	return tableNetworkMap
+}
+
+//NewElement allocates and returns an endpoint value
+func (d *DockerEpMap) NewElement() interface{} {
+	return &DockerEpVal{}
+}
+
+//Add adds a value to the map with the specified key
+func (d *DockerEpMap) Add(k string, v interface{}) error {
+	val, ok := v.(*DockerEpVal)
+	if !ok {
+		return fmt.Errorf("Invalid value type %t", v)
+	}
+	d.m[k] = val
+	return nil
+}
+
 //DockerNwMap maintains the Docker Network UUID to ciao Network mappings
 type DockerNwMap struct {
 	sync.Mutex
 	m map[string]*DockerNwVal //index: Docker Network UUID
 }
 
+//NewTable creates a new map
+func (d *DockerNwMap) NewTable() {
+	d.m = make(map[string]*DockerNwVal)
+}
+
+//Name provides the name of the map
+func (d *DockerNwMap) Name() string {
+	return tableEndPointMap
+}
+
+//NewElement allocates and returns an network value
+func (d *DockerNwMap) NewElement() interface{} {
+	return &DockerNwVal{}
+}
+
+//Add adds a value to the map with the specified key
+func (d *DockerNwMap) Add(k string, v interface{}) error {
+	val, ok := v.(*DockerNwVal)
+	if !ok {
+		return fmt.Errorf("Invalid value type %t", v)
+	}
+	d.m[k] = val
+	return nil
+}
+
 // DockerPlugin describes a single instance of a docker plugin
 // In the current design the plugin acts as an IPAM and Network Plugin
 type DockerPlugin struct {
@@ -756,10 +822,10 @@ func (d *DockerPlugin) Init() error {
 	if err := d.DbInit(DockerPluginCfg.DataDir); err != nil {
 		return err
 	}
-	if err := d.DbMapRebuild(tableNetworkMap, &d.DockerNwMap); err != nil {
+	if err := d.DbTableRebuild(&d.DockerNwMap); err != nil {
 		return err
 	}
-	if err := d.DbMapRebuild(tableEndPointMap, &d.DockerEpMap); err != nil {
+	if err := d.DbTableRebuild(&d.DockerEpMap); err != nil {
 		return err
 	}